[media] media: Add 64--32 bit compat ioctl handler

Provide an ioctl handler for 32-bit binaries on 64-bit systems.

Signed-off-by: Sakari Ailus <[e-mail]>
Acked-by: Laurent Pinchart <[e-mail]>
Tested-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/media-devnode.c

···
 	return mdev->fops->poll(filp, poll);
 }
 
-static long media_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+static long
+__media_ioctl(struct file *filp, unsigned int cmd, unsigned long arg,
+	      long (*ioctl_func)(struct file *filp, unsigned int cmd,
+				 unsigned long arg))
 {
 	struct media_devnode *mdev = media_devnode_data(filp);
 
-	if (!mdev->fops->ioctl)
+	if (!ioctl_func)
 		return -ENOTTY;
 
 	if (!media_devnode_is_registered(mdev))
 		return -EIO;
 
-	return mdev->fops->ioctl(filp, cmd, arg);
+	return ioctl_func(filp, cmd, arg);
 }
+
+static long media_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct media_devnode *mdev = media_devnode_data(filp);
+
+	return __media_ioctl(filp, cmd, arg, mdev->fops->ioctl);
+}
+
+#ifdef CONFIG_COMPAT
+
+static long media_compat_ioctl(struct file *filp, unsigned int cmd,
+			       unsigned long arg)
+{
+	struct media_devnode *mdev = media_devnode_data(filp);
+
+	return __media_ioctl(filp, cmd, arg, mdev->fops->compat_ioctl);
+}
+
+#endif /* CONFIG_COMPAT */
 
 /* Override for the open function */
 static int media_open(struct inode *inode, struct file *filp)
···
 	.write = media_write,
 	.open = media_open,
 	.unlocked_ioctl = media_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = media_compat_ioctl,
+#endif /* CONFIG_COMPAT */
 	.release = media_release,
 	.poll = media_poll,
 	.llseek = no_llseek,

include/media/media-devnode.h

···
 	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
 	unsigned int (*poll) (struct file *, struct poll_table_struct *);
 	long (*ioctl) (struct file *, unsigned int, unsigned long);
+	long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
 	int (*open) (struct file *);
 	int (*release) (struct file *);
 };